Shavuos is unfortunately over. Chagim are a huuuge deal. We must squeeze out of them every drop of ruchniyos that we can.
A few personal questions:
1] How are you different now than you were before the chag?
2] What kabbalos did you take upon yourself?
3] What percentage of the chag was gashmiyus and what percentage ruchniyos?
4] Did you really learn all night? How much did you sleep during the day? How was your davening? What did this teach you about next Shavuos?
It is not too late. Every day we say נותן התורה - the Giver [present tense] of the Torah. EVERY DAY is a new kabbolos hatorah.